INTRODUCTION. IX 



many cases where there is even a cons iderable probability of these 

 being synonyms ; since it appears to the author that it is almost as 

 great an evil to abolish a well-known name without being almost 

 absolutely certain of the necessity of the step, as it is to introduce 

 new names. The aid of asterisks has, however, been called in to 

 point out some of these doubtful names. Whether many of the 

 generic terms which have been applied to Dinosaurians and other 

 Reptiles from the strata of North America, which are evidently 

 closely allied to European forms, are really entitled to stand, remains 

 to be proved ; but since in most cases the names applied to the 

 European forms have the priority, the question does not affect the 

 majority of those employed in the present work. 



In many instances, however, such American generic names have 

 been taken as the foundation for family names ; but since there is a 

 possibility of some of these being eventually relegated to the rank 

 of synonyms, the earlier European names have generally been sub- 

 stituted as the foundation for family names \ In some cases also, 

 families have been admitted which it may eventually be found 

 advisable to fuse with others. A word is also desirable in regard to 

 the supercession of generic and specific names, of which the type 

 specimens have never been figured. The writer is not one of those 

 who think that a name should never be recognized until the tj T pe 

 has been figured 2 : but in cases where the original description is 

 altogether unsatisfactory and difficult to recognize, and no figure 

 of the type has been subsequently given, he considers that if, 

 after a reasonable interval, other specimens have been described and 

 figured under a new name, that name is entitled to supersede the 

 old one. If, however, an author having the original type of an un- 

 figured but described species before him, ignores the old name, 

 even if insufficiently characterized, to impose a new one, then there 

 appears good reason for reviving the older name. The former 

 course has been followed in the instance of the species of the genus 



J Many writers maintain that family names are entitled to rank by priority 

 like generic and specific ones. It is, however, merely, so to speak, by accident 

 that the earlier generic names were not made types of families ; and the writer 

 thinks that when this has been omitted the fair course would be to take such 

 names as the foundation for families, rather than to elevate some newly made 

 term to this rank. That family names should stand when the genera on which 

 they were based have been reduced to the rank of synonyms is practically an 

 absurdity. Thus, should it be found eventually advisable to include the genus 

 Stegosaurus in Omosattrus, it would be absurd to speak of the Stcgosaurida, or 

 Stegosaurus-like reptiles, when no such reptile as Stegosaurus existed. 



- As proposed at the Berlin Geological Congress. 



